The present invention relates to pumps of the type used to pump debris containing liquid. In particular, the invention relates to of the type used in surgical procedures.
Transport of solid matter via a liquid carrier is sometimes referred to as two-phase flow. Increasing use of catheters to deliver energy into the body and extract debris from the body in carrying out less invasive surgical procedures increases the desirability for systems which can, without clogging, remove solid particles by better holding them in suspension in a liquid carrier.
In some surgical procedures, continuous uninterrupted contact of the surgical scalpel or appliance with the material being treated can reduce its effectiveness. The reasons for this include tissue blocking the flow of carrier fluid; the material being cut revolving or oscillating in synchrony with the cutting tip, thereby reducing or eliminating the displacement of the cutter edge relative to the material and greatly reducing cutting efficiency; the material being cut not lunging into the cutting appliance with enough velocity to enable deep bites, thereby seriously hampering cutting speed; the material being cut conforming to the shape of the cutting appliance and, thus, not providing the cutter with fresh promontories to dissect. The result of any of the above problems is reduced speed of cutting.
By way of example, suction (aspirating) tubes or catheters are frequently used in clinical practice to evacuate matter from the human body. Suction is also used to draw tissue or deposits into the operating orifice of endoscopic or percutaneous scalpels in order to improve the contact of the cutter blades with the tissue to be masticated. The various commercial appliances now available for dissection and removal of torn meniscus fragments via percutaneous artheroscopy are examples of suction enhancement of cutting and suction removal of fragments. Suction electrodes for enhancing contact with tissue before electrocoagulation or removal of blood from a lesion to be coagulated have been sold for several years. Surgeons routinely use suction tubes in open surgery to clear blood and irrigation fluids from operating sites in order to better visualize the wound. Surgeons also use suction to excapsulate tumors which have been coagulated.
In all of the foregoing procedures, there is a high likelihood of clogging the suction tube or its associated ports. In surgical procedures which require suction, the input port is frequently obstructed by a flap of tissue which occludes the input port of the suction tube. In endoscopic or percutaneous procedures, the clogging of a catheter can result in excessive clinical delays while patency is re-established.
In view of the numerous procedures in which a non-clogging pump is required, such a device would be highly desirable.